The disclosed novel polyurethane polyol is derived from CARDANOL 3-(8-pentadecenyl)phenol, a product obtained from natural CNSL and is the main constituent of technical grade CNSL. Cashew Nut Shell Liquid (CNSL) has been known for years to contain compounds useful in various aspects of chemical industry. Technical grade or distilled CNSL is a commercially available product. It comprises in major proportions (typically more than 95% by weight) a material also sold separately under the trade name CARDANOL 3-(8-pentadecenyl)phenol, which is a substituted phenol possessing an alkyl chain of average unsaturation two double bonds in the meta position. Other minor constituents are cardol and 2-methyl cardol. CARDANOL 3-(8-pentadecenyl)phenol is used in many industrial applications such as coatings, resins, adhesives and other novel products. Novel polyols of the present invention are used in making rigid PU foams. The reaction of diisocyanate and or poly isocyanate with the hydroxyl groups of polyol co reactants and blowing agents (such as water, dichloromethane, cyclopentane and HCFC's) are used to produce polyurethane foams. Rigid polyurethane foams are primarily used for thermal insulation. Polyurethane foams constitute the largest category of cellular polymeric materials. They offer an attractive balance of performance characteristics such as aging properties, mechanical strength, elastic properties, and chemical resistance, insulating properties and cost.
Polyols based on petroleum resources are costly and scarce. Some of them such as polyester polyols also possess poor resistance to hydrolysis and poor abrasion resistance. It is of particular interest to develop polyols which may be easily and cheaply obtained form readily available and renewable resource material such as CNSL. Its use in the preparation of polyurethane polyols suitable for making rigid foams is not reported. For the preparation of polyols from renewable resources like vegetable oils several processes are disclosed in the literature. Reference may be made to U.S. Pat. No. 6,107,433 which disclose process for preparing vegetable oil based polyol from castor oil by oxidation of the side chain unsaturation using per acids and a method for making polyurethane castings using these polyols. In another patent [U.S. Pat. No. 4,825,004] a process for the production of alkane polyols starting from natural fatty acid derivatives by per acid oxidation is disclosed. However, these prior art processes have not been reported with cardanol before for making polyurethane polyols. Because of the unique molecular structure of cardanol (a long unsaturated side alkyl chain on the benzene ring) the disadvantages disclosed in the prior art process, is not applicable in the case of cardanol. For example, the hydrolysis of triglyceride oils is not expected in the case of cardanol.